Where do creative design ideas come from? Cognitive scientists have discovered that people inevitably build new ideas from their prior knowledge and experiences (Marsh et al. 1999; Ward 1994). While these prior experiences can serve as sources of inspiration (Eckert and Stacey 1998) and drive sustained creation of ideas that are both new and have high potential for impact (Helms et al. 2009; Hargadon and Sutton 1997), they can also lead designers astray: for instance, designers sometimes incorporate undesirable features from existing solutions (Jansson and Smith 1991; Linsey et al. 2010), and prior knowledge can make it difficult to think of alternative approaches (German and Barrett 2005; Wiley 1998). This raises the question: what features of potential inspirational sources can predict their value (and/or potential harmful effects)? In this chapter, we examine how the conceptual distance of sources relates to their inspirational value.

12.1 Background

12.1.1 Research Base

What do we mean by conceptual distance? Consider the problem of e-waste accumulation: the world generates 20–50 million metric tons of e-waste every year, yielding environmentally hazardous additions to landfills. A designer might approach this problem by building on near sources like smaller scale electronics reuse/recycle efforts, or by drawing inspiration from a far source like edible food packaging technology (e.g., to design reusable electronics parts). What are the relative benefits of different levels of source conceptual distance along a continuum from near to far?

Many authors, principally those studying the role of analogy in creative problem solving, have proposed that conceptually far sources—structurally similar ideas with many surface (or object) dissimilarities—are the best sources of inspiration for creative breakthroughs (Gentner and Markman 1997; Holyoak and Thagard 1996; Poze 1983; Ward 1998). This proposal—here called the Conceptual Leap Hypothesis—is consistent with many anecdotal accounts of creative breakthroughs, from Kekule’s discovery of the structure of benzene by visual analogy to a snake biting its tail (Findlay 1965), to George Mestral’s invention of Velcro by analogy to burdock root seeds (Freeman and Golden 1997), to more recent case studies (Enkel and Gassmann 2010; Kalogerakis et al. 2010).

However, empirical support for this proposal is mixed. Some studies have shown an advantage of far over near sources for novelty, quality, and flexibility of ideation (Chan et al. 2011; Chiu and Shu 2012; Dahl and Moreau 2002; Gonçalves et al. 2013; Hender et al. 2002); but, some in vivo studies of creative cognition have not found strong connections between far sources and creative mental leaps (Chan and Schunn 2014; Dunbar 1997), and other experiments have demonstrated equivalent benefits of far and near sources (Enkel and Gassman 2010; Malaga 2000). Relatedly, Tseng et al. (2008) showed that far sources were more impactful after ideation had already begun (vs. before ideation), providing more functionally distinct ideas than near or control, but both far and near sources led to similar levels of novelty. Similarly, Wilson et al. (2010) showed no advantage of far over near sources for novelty of ideas (although near but not far sources decreased variety of ideas). Fu et al. (2013) even found that far sources led to lower novelty and quality of ideas than near sources. Thus, more empirical work is needed to determine whether the Conceptual Leap Hypothesis is well supported. Further, Fu et al. (2013) argue there is an inverted U-shape function in which moderate distance is best, suggesting the importance of conceptualizing and measuring distance along a continuum.

12.1.2 Impetus for the Current Work

Key methodological shortcomings in prior work further motivate more and better empirical work. Prior studies may be too short (typically 30 min to 1 h) to convert far sources into viable concepts. To successfully use far sources, designers must spend considerable cognitive effort to ignore irrelevant surface details, attend to potentially insightful structural similarities, and adapt the source to the target context. Additionally, many far sources may yield shallow or unusable inferences (e.g., due to non-alignable differences in structural or surface features; Perkins 1997); thus, designers might have to sift through many samples of far sources to find “hidden gems.” These higher processing costs for far sources might partially explain why some studies show a negative impact of far sources on the number of ideas generated (Chan et al. 2011; Hender et al. 2002). In the context of a short task, these processing costs might take up valuable time and resources that could be used for other important aspects of ideation (e.g., iteration, idea selection); in contrast, in real-world design contexts, designers typically have days, weeks, or even months (not an hour) to consider and process far sources.

A second issue is a lack of statistical power. Most existing experimental studies have N ≤ 12 per treatment cell (Chiu and Shu 2012; Hender et al. 2002; Malaga 2000); only four studies had N ≥ 18 (Chan et al. 2011; Fu et al. 2013; Gonçalves et al. 2013; Tseng et al. 2008), and they are evenly split in support/opposition for the benefits of far sources. Among the few correlational studies, only Dahl and Moreau (2002) had a well powered study design in this regard, with 119 participants and a reasonable range of conceptual distance. Enkel and Gassmann (2010) only examined 25 cases, all of which were cases of cross-industry transfer (thus restricting the range of conceptual distance being considered). This lack of statistical power may have led to a proliferation of false negatives (potentially exacerbated by small or potentially zero effects at short time scales), but possibly also severely overestimated effect sizes or false positives (Button et al. 2013); more adequately powered studies are needed for more precise estimates of the effects of conceptual distance.

A final methodological issue is problem variation. Many experimental studies focused on a single design problem. The inconsistent outcomes in these studies may be partially due to some design problems having unique characteristics, e.g., coincidentally having good solutions that overlap with concepts in far sources. Indeed, Chiu and Shu (2012), who examined multiple design problems, observed inconsistent effects across problems. Other investigations of design stimuli have also observed problem variation for effects (Goldschmidt and Smolkov 2006; Liikkanen and Perttula 2008).

This paper contributes to theories of design inspiration by (1) reporting the results of a study that addresses these methodological issues to yield clearer evidence, and (2) (to foreshadow our results) reexamining theories of design inspiration and conceptual distance in light of accumulating preponderance of evidence against the Conceptual Leap Hypothesis.

12.2 Methods

12.2.1 Overview of Research Context

The current work is conducted in the context of OpenIDEO (www.openideo.com), a Web-based crowdsourced innovation platform that addresses a range of social and environmental problems (e.g., managing e-waste, increasing accessibility in elections). The OpenIDEO designers, with expertise in design processes, guide contributors to the platform through a structured design process to produce concepts that are ultimately implemented for real-world impact (“Impact Stories,” n.d.). For this study, we focus on three crucial early stages in the process: first, in the inspiration phase (lasting between 1.5 and 4 weeks, M = 3.1), contributors post inspirations (e.g., descriptions of solutions to analogous problems and case studies of stakeholders), which help to define the problem space and identify promising solution approaches; then, in the concepting phase (lasting the next 2–6 weeks, m = 3.4), contributors post concepts, i.e., specific solutions to the problem. Figure 12.1 shows an example concept; it is representative of the typical length and level of detail in concepts, i.e., ~150 words on average, more detail than one or two words/sentences/sketches, but less detail than a full-fledged design report/presentation or patent application. Finally, a subset of these concepts is shortlisted by an expert panel (composed of the OpenIDEO designers and a set of domain experts/stakeholders) for further refinement, based on their creative potential. In later stages, these concepts are refined and evaluated in more detail, and then a subset of them is selected for implementation. We focus on the first three stages given our focus on creative ideation (the later stages involve many other design processes, such as prototyping).

Fig. 12.1
figure 1

Example concept illustrating the typical amount of detail per concept

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The OpenIDEO platform has many desirable properties as a research context for our work, including the existence of multiple design problems, thousands of concepts and inspirations, substantive written descriptions of ideas to enable efficient text-based analyses, and records of feedback received for each idea, another critical factor in design success. A central property for our research question is the explicit nature of sources of inspiration in the OpenIDEO workflow. The site encourages contributors to build on others’ ideas. Importantly, when posting concepts or inspirations, contributors are prompted to cite any concepts or inspirations that serve as sources of inspiration for their idea. Also, when browsing other concepts/inspirations, they are also able to see concepts/inspirations the given concept/inspiration “built upon” (i.e., cited as explicit sources of inspiration; see Fig. 12.2). This culture of citing sources is particularly advantageous, given that people generally forget to monitor or cite their sources of inspiration (Brown and Murphy 1989; Marsh et al. 1997), and our goal is to study the effects of source use. While users might still forget to cite sources, these platform features help ensure higher rates of source monitoring than other naturalistic ideation contexts. We note that this operationalization of sources as self-identified citations precludes consideration of implicit stimulation; however, the Conceptual Leap Hypothesis may be more applicable to conscious inspiration processes (e.g., analogy, for which conscious processing is arguably an important defining feature; Schunn and Dunbar 1996).

Fig. 12.2
figure 2

Depiction of OpenIDEO citation workflow. When posting concepts/inspirations, users are prompted to cite concepts/inspirations they “build upon” by dragging bookmarked concepts/inspirations (middle panel) to the citation area (left panel). Users can also search for related concepts/inspirations at this step (middle panel). These cited sources then show up as metadata for the concept/inspiration (right panel)

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12.2.2 Sample and Initial Data Collection

The full dataset for this study consists of 2341 concepts posted for 12 completed challenges by 1190 unique contributors, citing 4557 unique inspirations; 241 (10%) of these concepts are shortlisted for further refinement. See Table 12.2 for a description of the 12 challenges (with some basic metadata on each challenge). Figure 12.3 shows the full-text design brief for two challenges.

Fig. 12.3
figure 3

Full-text of challenge briefs from two OpenIDEO challenges

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With administrator permission, we downloaded all inspirations and concepts (which exist as individual webpages) and used an HTML parser to extract the following data and metadata:

  1. (1)

    Concept/inspiration author (who posted the concept/inspiration)

  2. (2)

    Number of comments (before the refinement phase)

  3. (3)

    Shortlist status (yes/no)

  4. (4)

    List of cited sources of inspiration

  5. (5)

    Full-text of concept/inspiration.

Not all concepts cited inspirations as sources. Of the 2341 concepts, 707 (posted by 357 authors) cited at least one inspiration, collectively citing 2245 unique inspirations. 110 of these concepts (~16%) were shortlisted (see Table 12.1 for a breakdown by challenge). This set of 707 concepts is the primary sample for this study; the others serve as a contrast to examine the value of explicit building at all on prior sources, and to aid in interpretation of any negative or positive effects of variations in distance. Because we only collected publicly available data, we do not have complete information on the expertise of all contributors: however, based on their public profiles on OpenIDEO, at least 1/3 of the authors in this sample are professionals in design-related disciplines (e.g., user experience/interaction design, communication design, architecture, product/industrial design, entrepreneurs and social innovators, etc.) and/or domain experts or stakeholders (e.g., urban development researcher contributing to the vibrant-cities challenge, education policy researcher contributing to the youth-employment challenge, medical professional contributing to the bone marrow challenge). Collectively, these authors accounted for approximately half of the 707 concepts in this study.

Table 12.1 Descriptions and number of posts for OpenIDEO challenges in final analysis sample
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We analyze the impact of the distance of inspirations (and not cited concepts) given our focus on ideation processes during “original” or nonroutine design, where designers often start with a problem and only “inspirations” (e.g., information about the problem or potentially related designs) rather than routine design (e.g., configuration or parametric design), where designers might be modifying or iterating on existing solutions rather than generating novel ones (Chakrabarti 2006; Dym 1994; Gero 2000; Ullman 2002). The Conceptual Leap Hypothesis maps most clearly to nonroutine design.

12.2.3 Measures

12.2.3.1 Creativity of Concepts

We operationalize concept creativity as whether a concept gets shortlisted. Shortlisting is done by a panel of expert judges, including the original challenge sponsors, who have spent significant time searching for and learning about existing approaches, and the OpenIDEO designers, who are experts in the general domain of creative design, and who have spent considerable time upfront with challenge sponsors learning about and defining the problem space for each challenge.

An expert panel is widely considered a “gold standard” for measuring the creativity of ideas (Amabile 1982; Baer and McKool 2009; Brown 1989; Sawyer 2012). Further, we know from conversations with the OpenIDEO team that the panel’s judgments combine consideration of both novelty and usefulness/appropriateness (here operationalized as potential for impact; A. Jablow, personal communication, May 1, 2014), the standard definition of creativity (Sawyer 2012). Since OpenIDEO challenges are novel and unsolved, successful concepts are different from (and, perhaps more importantly, significantly better than) the existing unsatisfactory solutions. We use shortlist (rather than win status) given our focus on the ideation phase in design (vs. convergence/refinement, which happens after concepts are shortlisted, and can strongly influence which shortlisted concepts get selected as “winners” for implementation).

12.2.3.2 Conceptual Distance

12.2.3.2.1 Measurement Approach

Measuring conceptual distance is a major methodological challenge, especially when studying large samples of ideation processes (e.g., many designs across many design problems). The complex and multifaceted nature of typical design problems can make it difficult to distinguish “within” and “between” domain sources in a consistent and principled manner. Further, using only a binary scale risks losing variance information that could be critical for converging on a more precise understanding of the effects of conceptual distance (e.g., curvilinear effects across the continuum of distance). Continuous distance measures are an attractive alternative, but can be extremely costly to obtain at this scale, especially for naturalistic sources (e.g., relatively developed text descriptions vs. simple sketches or one-to-two sentence descriptions). Human raters may suffer from high levels of fatigue, resulting in poor reliability or drift of standards.

We address this methodological challenge with probabilistic topic modeling (Blei 2012; Steyvers and Griffiths 2007), a major computational approach for understanding large collections of unstructured text. They are similar to other unsupervised machine learning methods—e.g., K-means clustering, and Latent Semantic Analysis (Deerwester et al. 1990)—but distinct in that they emphasize human understanding of not just the relationship between documents in a collection, but the “reasons” for the hypothesized relationships (e.g., the “meaning” of particular dimensions of variation), largely because the algorithms underlying these models tend to produce dimensions in terms of clusters of tightly co-occurring words. Thus, they have been used most prominently in applications where understanding of a corpus, not just information retrieval performance, is a high priority goal, e.g., knowledge discovery and information retrieval in repositories of scientific papers (Griffiths and Steyvers 2004), describing the structure and evolution of scientific fields (Blei and Lafferty 2006, 2007), and discovering topical dynamics in social media use (Schwartz et al. 2013).

We use Latent Dirichlet Allocation (LDA; Blei et al. 2003), the simplest topic model. LDA assumes that documents are composed of a mixture of latent “topics” (occurring with different “weights” in the mixture), which in turn generate the words in the documents. LDA defines topics as probability distributions over words: for example, a “genetics” topic can be thought of as a probability distribution over the words {phenotype, population, transcription, cameras, quarterbacks}, such that words closely related to the topic {phenotype, population, transcription} have a high probability in that topic, and words not closely related to the topic {cameras, quarterbacks} have a very low probability. Using Bayesian statistical learning algorithms, LDA infers the latent topical structure of the corpus from the co-occurrence patterns of words across documents. This topical structure includes 1) the topics in the corpus, i.e., the sets of probability distributions over words, and 2) the topic mixtures for each document, i.e., a vector of weights for each of the corpus topics for that document. We can derive conceptual similarity between any pair of documents by computing the cosine between their topic-weight vectors. In essence, documents that share dominant topics in similar relative proportions are the most similar.

Here, we used the open-source MAchine Learning for LanguagE Toolkit (MALLET; McCallum 2002) to train an LDA model with 400 topics for all documents in the full dataset, i.e., 2341 concepts, 4557 inspirations, and 12 challenge briefs (6910 total documents). Additional technical details on the model-building procedure are available in Appendix 1. Resulting cosines between inspirations and the challenge brief ranged from 0.01 to 0.91 (M = 0.21, SD = 0.18), a fairly typical range for large-scale information retrieval applications (Jessup and Martin 2001).

12.2.3.2.2 Validation

Since we use LDA’s measures of conceptual distance as a substitute for human judgments, we validate the adequacy of our topic model using measures of fit with human similarity judgments on a subset of the data by trained human raters.

Five trained raters used a Likert-type scale to rate 199 inspirations from one OpenIDEO challenge for similarity to their challenge brief, from 1 (very dissimilar) to 6 (extremely similar). Raters were given the intuition that the rating would approximately track the proportion of “topical overlap” between each inspiration and the challenge brief, or the extent to which they are “about the same thing.” The design challenge context was explicitly deemphasized, so as to reduce the influence of individual differences on perceptions of the “relevance” of sources of inspiration. Thus, the raters were instructed to treat all the documents as “documents” (e.g., an article about some topics, vs. “problem solution”) and consciously avoid judging the “value” of the inspirations, simply focusing on semantic similarity. Raters listed major topics in the challenge brief and evaluated each inspiration against those major topics. To ensure internal consistency, the raters also sorted the inspirations by similarity after every 15–20 judgments. They then inspected the rank ordering and composition of inspirations at each point in the scale, and made adjustments if necessary (e.g., if an inspiration previously rated as “1” now, in light of newly encountered inspirations, seemed more like a “2” or “3”). Although the task was difficult, the mean ratings across raters had an acceptable aggregate consistency intra-class correlation coefficient [ICC(2,5)] of 0.74 (mean inter-coder correlation = 0.36). LDA cosines correlated highly, at r = 0.51, 95% CI = [0.40, 0.60], with the continuous human similarity judgments (see Fig. 12.4A). We note that this correlation is better than the highest correlation between human raters (r = 0.48), reinforcing the value of automatic coding methods for this difficult task.

Fig. 12.4
figure 4

a Scatterplot of LDA cosines vs. averaged human continuous similarity judgments for inspirations in the e-waste challenge. b Mean cosine against the challenge brief for within—versus between-domain inspirations

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For comparability with prior work, we also measure fit with binary (within- vs. between-domain) distance ratings. Two raters also classified 345 inspirations from a different challenge as either within- or between-domain. Raters first collaboratively defined the problem domain, focusing on the question, “What is the problem to be solved?” before rating inspirations. Within-domain inspirations were information about the problem (e.g., stakeholders, constraints) and existing prior solutions for very similar problems, while between-domain inspirations were information/solutions for analogous or different problems. Reliability for this measure was acceptable, with an overall average kappa of 0.78 (89% agreement). All disagreements were resolved by discussion. Similar to the continuous similarity judgments, the point biserial correlation between the LDA-derived cosine and the binary judgments was also high, at 0.50, 95% CI = [0.42, 0.58]. The mean cosine to the challenge brief was also higher for within-domain (M = 0.49, SD = 0.25, N = 181) vs. between-domain inspirations (M = 0.23, SD = 0.20, N = 164), d = 1.16, 95% CI = [1.13, 1.19] (see Fig. 12.4b), further validating the LDA approach to measuring distance. Figure 12.5 shows examples of a near and far inspiration (from the e-waste challenge), along with the top 3 LDA topics (represented by the top 5 words for that latent topic), computed cosine vs. its challenge brief, and human similarity rating. The top 3 topics for the challenge brief are {waste, e, recycling, electronics, electronic}, {waste, materials, recycling, recycled, material}, and {devices, electronics, electronic, device, products}, distinguishing e-waste, general recycling, and electronics products topics. These examples illustrate how LDA is able to effectively extract the latent topical mixture of the inspirations from their text (inspirations with media also include textual descriptions of the media, mitigating concerns about loss of semantic information due to using only text as input to LDA) and also capture intuitions about variations in conceptual distance among inspirations: a document about different ways of assigning value to possessions is intuitively conceptually more distant from the domain of e-waste than a document about a prior effort to address e-waste.

Fig. 12.5
figure 5

Topics found by LDA within examples of near and far inspirations for the e-waste challenge

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The near and far examples depicted in Fig. 12.5 also represent the range of conceptual distance measured in this dataset, with the near inspiration’s cosine of 0.64 representing approximately the 90th percentile of similarity to the challenge domain, and the far inspiration’s cosine of 0.01 representing approximately the 10th percentile of similarity to the challenge domain. Thus, the range of conceptual distance of inspirations in this data spans approximately from sources that are very clearly within the domain (e.g., an actual solution for the problem of electronic waste involving recycling of materials) to sources that are quite distant, but not obviously random (e.g., an observation of how people assign emotional value to relationships and artifacts). This range most likely excludes the “too far” example designs studied in Fu et al. (2013) or the “opposite stimuli” used in Chiu and Shu (2012).

12.2.3.2.3 Final Distance Measures

The challenge briefs varied in length and specificity across challenges, as did mean raw cosines for inspirations. But, these differences in mean similarity were much larger, d = 1.90, 95% CI = [1.85–1.92] (for 80 inspirations from 4 challenges with maximally different mean cosines), than for human similarity judgments (coded separately but with the same methodology as before), d = 0.18, 95% CI = [–0.05 to 0.43]. This suggested that between-challenge differences were more an artifact of variance in challenge brief length/specificity. Thus, to ensure meaningful comparability across challenges, we normalized the cosines by computing the z-score for each inspiration’s cosine relative to other inspirations from the same challenge before analyzing the results in the full dataset. However, similar results are found using raw cosines, but with more uncertainty in the statistical coefficient estimates.

We then subtracted the cosine z-score from zero such that larger values meant more distant. From these “reversed” cosine z-scores, two different distance measures were computed to tease apart possibly distinct effects of source distance: (1) max distance (DISTmax), i.e., the distance of a concept’s furthest source from the problem domain and (2) mean distance (DISTmean) of the concept’s sources. DISTmax estimates “upper bounds” for the benefits of distance: do the best ideas really come from the furthest sources? DISTmean capitalizes on the fact that many concepts relied on multiple inspirations and estimates the impact of the relative balance of relying on near vs. far sources (e.g., more near than far sources, or vice versa).

12.2.3.3 Control Measures

Given our correlational approach, it is important to identify and rule out or adjust for other important factors that may influence the creativity of concepts (particularly in the later stages, where prototyping and feedback are especially important) and may be correlated with the predictor variables.

Feedback. Given the collaborative nature of OpenIDEO, we reasoned that feedback in the form of comments (labeled here as FEEDBACK) influences success. Comments can offer encouragement, raise issues/questions, or provide specific suggestions for improvement, all potentially significantly enhancing the quality of the concept. Further, feedback may be an alternate pathway to success via source distance, in that concepts that build on far sources may attract more attention and therefore higher levels of feedback, which then improve the quality of the concept.

Quality of cited sources. Concepts that build on existing high-quality concepts (e.g., those who end up being shortlisted or chosen as winners) have a particular advantage of being able to learn from the mistakes and shortcomings, good ideas, and feedback in these high-quality concepts. Thus, as a proxy measure of quality, the number of shortlisted concepts a given concept builds upon (labeled SOURCESHORT) could be a large determinant of a concept’s success.

12.2.4 Analytic Approach

We are interested in predicting the creative outcomes of 707 concepts, posted by 357 authors for 12 different design challenges. Authors are not cleanly nested within challenges, nor vice versa; our data are cross-classified, with concepts cross-classified within both authors and challenges (see Fig. 12.6). This cross-classified structure violates assumptions of uniform independence between concepts: concepts posted by the same author or within the same challenge may be more similar to each other. Failing to account for this nonindependence could lead to overestimates of the statistical significance of model estimates (i.e., make unwarranted claims of statistically significant effects). This issue is exacerbated when testing for small effects. Additionally, modeling between-author effects allows us to separate author effects (e.g., higher/lower creativity) from the impact of sources on individual concepts. Thus, we employ generalized linear mixed models (also called hierarchical generalized linear models) to model both fixed effects (of our independent and control variables) and random effects (potential variation of the outcome variable attributable to author- or challenge-nesting and also potential between-challenge variation in the effect of distance) on shortlist status (a binary variable, which requires logistic, rather than linear, regression).

Fig. 12.6
figure 6

Illustrated cross-classified structure of the data

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An initial model predicting the outcome with only the intercept and between-challenge and -author variation confirms the presence of significant nonindependence, with between-author and between-challenge variation in shortlist outcomes estimated at 0.44, and 0.50, respectively. The intra-class correlations for author-level and challenge-level variance in the intercept are ~0.11 and 0.13, respectively, well above the cutoff recommended by Raudenbush and Bryk (2002).Footnote 1

12.3 Results

12.3.1 Descriptive Statistics

On average, 16% of concepts in the sample get shortlisted (see Table 12.2). DISTmean is centered approximately at 0, reflecting our normalization procedure. Both DISTmax and DISTmean have a fair degree of negative skew. SOURCESHORT and FEEDBACK have strong positive skew (most concepts either have few comments or cite 0 or 1 shortlisted concepts).

Table 12.2 Descriptive statistics
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There is a strong positive relationship between DISTmax and DISTmean (see Table 12.3). All variables have significant bivariate correlations with SHORTLIST except for DISTmax; however, since it is a substantive variable of interest, we will model it nonetheless. Controlling for other variables might enable us to detect subtle effects.

Table 12.3 Bivariate correlations
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12.3.2 Statistical Models

We estimated separate models for the effects of DISTmax and DISTmean, each controlling for challenge-and author-nesting, FEEDBACK, and SHORTSOURCE.

12.3.2.1 Max Distance

Our model estimated an inverse relationship between DISTmax and Pr (shortlist), such that a 1-unit increase in DISTmax predicted a 0.33 decrease in the log-odds of being shortlisted, after accounting for the effects of FEEDBACK, SHORTSOURCE, and challenge- and author-level nesting, p < .05 (see Appendix 2 for technical details on the statistical models). However, this coefficient was estimated with considerable uncertainty, as indicated by the large confidence intervals (coefficient could be as small as −0.06 or as large as −0.60); considering also the small bivariate correlation with SHORTLIST, we are fairly certain that the “true” coefficient is not positive (contra the Conceptual Leap Hypothesis), but we are quite uncertain about its magnitude.

Figure 12.7 visually displays the estimated relationship between DISTmax and Pr (shortlist), evaluated at mean values of feedback and shortlisted sources. To aid interpretation, we also plot the predicted Pr (shortlist) for concepts that cite no sources using a horizontal gray bar (bar width indicates uncertainty in estimate of Pr (shortlist)): concepts with approximately equivalent amounts of feedback (i.e., mean of 8.43) have a predicted Pr (shortlist = 0.09, 95% CI = [0.07 to 0.11]; using a logistic model, the coefficient for “any citation” (controlling for feedback) is 0.31, 95% CI = [0.01 to 0.62]). This bar serves as an approximate “control” group, allowing us to interpret the effect not just in terms of the effects of far sources relative to near sources, but also in comparison with using no sources. Comparing the fitted curve with this bar highlights how the advantage of citing versus not citing inspirations seems to be driven mostly by citing relatively near inspirations: Pr (shortlist) for concepts that cite far inspirations converges on that of no-citation concepts. We emphasize again that despite the uncertainty in the degree of the negative relationship between DISTmax and Pr (shortlist), the data do not support an inference that the best ideas are coming from the farthest inspirations: rather, relying on nearer rather than farther sources seems to lead to more creative design ideas. Importantly, this pattern of results was robust across challenges on the platform: the model estimated essentially zero between-challenge variation in the slope of DISTmax. χ2(2) = 0.05, p = 0.49 (see Fig. 12.8).

Fig. 12.7
figure 7

Model-fitted relationship between DISTmax and Pr (shortlist), evaluated at mean values of feedback and source shortlist. Grayed lines are fits with upper and lower limits for 95% CI for effect of DISTmax

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Fig. 12.8
figure 8

Overall and by-challenge model-fitted relationship between DISTmax and Pr (shortlist). Fitted values evaluated at mean values of feedback and source shortlist. Grayed lines are fits for each individual challenge

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12.3.2.2 Mean Distance

Similar results were obtained for DISTmean. There was a robust inverse relationship between DISTmean and Pr (shortlist), such that a 1-unit increase in DISTmean was associated with a decrease of approximately 0.40 in the log-odds of being shortlisted, p < .05. The estimates of this effect were obtained with similarly low precision regarding the magnitude of the effect, with 95% CI upper limit of at most B = −0.09 (but as high as −0.71). As shown in Fig. 12.9, as DISTmean increases, Pr (shortlist) approaches that of non-citing concepts, again suggesting (as with DISTmax) that the most beneficial sources appear to be ones that are relatively close to the challenge domain. Again, as with DISTmax, this pattern of results did not vary across challenges: our model estimated essentially zero between-challenge variation in the slope of DISTmean, χ2(2) = 0.07, p = .48 (see Fig. 12.10).

Fig. 12.9
figure 9

Model-fitted relationship between DISTmean and Pr (shortlist), evaluated at mean values of feedback and source shortlist. Grayed lines are fits with upper and lower limits for the 95% CI for the effect of DISTmean

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Fig. 12.10
figure 10

Overall and by-challenge model-fitted relationship between DISTmean and Pr (shortlist). Fitted values evaluated at mean values of feedback and source shortlist. Grayed lines are fits for each individual challenge

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12.4 Discussion

12.4.1 Summary and Interpretation of Findings

This study explored how the inspirational value of sources varies with their conceptual distance from the problem domain along the continuum from near to far. The study’s findings provide no support for the notion that the best ideas come from building explicitly on the farthest sources. On the contrary, the benefits of building explicitly on inspirations seem to accrue mainly for concepts that build more on near than far inspirations. Importantly, these effects were consistently found in all of the challenges, addressing concerns raised about potential problem variation, at least among nonroutine social innovation design problems.

12.4.2 Caveats and Limitations

Some caveats should be discussed before addressing the implications of this study. First, the statistical patterns observed here are conditional: i.e., we find an inverse relationship between conceptual distance of explicitly cited inspiration sources and Pr (shortlist). Our data are silent on the effects of distance for concepts that did not cite sources (where lack of citation could indicate forgetting of sources or lack of conscious building on sources).

There is a potential concern over range restriction or attrition due to our reliance on self-identified sources. However, several features of the data help to ameliorate this concern. First, concepts that did not cite sources were overall of lower quality; thus, it is unlikely that the inverse effects of distance are solely due to attrition (e.g., beneficial far inspirations not being observed). Second, the integration of citations and building on sources into the overall OpenIDEO workflow and philosophy of ideation also helps ameliorate concerns about attrition of far sources. Finally, the dataset included many sources that were quite far away, providing sufficient data to statistically test the effects of relative reliance on far sources (even if they are overall underreported). Nevertheless, we should still be cautious about making inferences about the impact of unconscious sources (since sources in this data are explicitly cited and therefore consciously built upon). However, as we note in the methods, the Conceptual Leap Hypothesis maps most cleanly to conscious inspiration processes (e.g., analogy).

Finally, some may be concerned that we have not measured novelty here. Conceivably, the benefits of distance may only be best observed for the novelty of ideas, and not necessarily quality, consistent with some recent work (Franke et al. 2013). However, novelty per se does not produce creativity; we contend that to fully understand the effects of distance on design creativity, we must consider its impacts on both novelty and quality together (as our shortlist measure does).

12.4.3 Implications and Future Directions

Overall, our results consistently stand in opposition to the Conceptual Leap Hypothesis. In tandem with prior opposing findings (reviewed in the introduction), our work lends strength to alternative theories of inspiration by theorists like Perkins (1983), who argues that conceptual distance does not matter, and Weisberg (2009, 2011), who argues that within-domain expertise is a primary driver of creative cognition. We should be clear that our findings do not imply that no creative ideas come from far sources (indeed, in our data, some creative ideas did come from far sources); rather, our data suggest that the most creative design ideas are more likely to come from relying on a preponderance of nearer rather than farther sources. However, our data do suggest that highly creative ideas can often come from relying almost not at all on far sources (as evidenced by the analyses with maximum distance of sources). These good ideas may arise from iterative, deep search, a mechanism for creative breakthroughs that may be often overlooked but potentially at least as important as singular creative leaps (Chan and Schunn 2014; Dow et al. 2009; Mecca and Mumford 2013; Rietzschel et al. 2007; Sawyer 2012; Weisberg 2011). In light of this and our findings, it may be fruitful to deemphasize the privileged role of far sources and mental leaps in theories of design inspiration and creative cognition.

How might this proposed theoretical revision be reconciled with the relatively robust finding that problem-solvers from outside the problem domain can often produce the most creative ideas (Hargadon and Sutton 1997; Franke et al. 2013; Jeppesen 2010)? Returning to our reflections on the potential costs of processing far sources, one way to reconcile the two sets of findings might be to hypothesize that expertise in the distant source domain enables the impact of distant ideas by bypassing the cognitive costs of deeply understanding the far domain, and filters out shallow inferences that are not likely to lead to deep insights. Hargadon and Sutton (1997) findings from their in-depth ethnographic study of the consistently innovative IDEO design firm are consistent with an expertise-mediation claim: the firm’s cross-domain-inspired innovations appeared to flow at the day-to-day process level mainly from deep immersion of its designers in multiple disciplines, and “division of expertise” within the firm, with brainstorms acting as crucial catalysts for involving experts from different domains on projects. However, studies directly testing expertise-mediation are scarce or nonexistent.

Further, the weight of the present data, combined with prior studies showing no advantage of far sources, suggests that considering alternative mechanisms of outside-domain advantage may be more theoretically fruitful: for instance, perhaps the advantage of outside-domain problem-solvers arises from the different perspectives they bring to the problem—allowing for more flexible and alternative problem representations, which may lead to breakthrough insights (Knoblich et al. 1999; Kaplan and Simon 1990; Öllinger et al. 2012). Domain outsiders may also have a looser attachment to the status quo or prior successful solutions by virtue of being a “newcomer” to the domain (Choi and Levine 2004)—leading to higher readiness to consider good ideas that challenge existing assumptions within the domain—rather than knowledge and transfer of different solutions per se.

Finally, it would be interesting to examine potential moderating influences of source processing strategies. In our data, closer sources were more beneficial, but good ideas also did come from far sources; however, as we have argued, it can be more difficult to convert far sources into viable concepts. Are there common strategies for effective conversion of far sources, and are they different from strategies for effectively building on near sources? For example, one effective strategy for building on sources while avoiding fixation is to use a schema-based strategy (i.e., extract and transfer abstract functional principles rather than concrete solution features; Ahmed and Christensen 2009; Yu et al. 2014). Are there processing strategies that expert creative designers apply uniquely to far sources (e.g., to deal with potentially un-alignable differences)? Answering this question can shed further light on the variety of ways designers can be inspired by sources to produce creative design ideas.

We close by noting the methodological contribution of this work. While we are not the first to use topic modeling to explore semantic meaning in a large collection of documents, we are the first to our knowledge to validate this method in the context of large-scale study of design ideas. We have shown that the topic model approach adequately captures human intuitions about the semantics of the design space, while providing dramatic savings in cost: indeed, such an approach can make more complex research questions (e.g., exploring pairwise distances between design idea or, tracing conceptual paths/moves in a design ideation session) much more feasible without sacrificing too much quality. We believe this approach can be a potentially valuable way for creativity researchers to study the dynamics of idea generation at scale, while avoiding the (previously inevitable) tradeoff between internal validity (e.g., having adequate statistical power) and external validity (e.g., using real, complex design problems and ideas instead of toy problems).